Sometimes a movie can start off perfectly well and maybe even sustain your interest for a good part of the running time and then BOOM it suddenly turns for the worse. Here's a very good example: I recently rented Staying Alive, the sequel to Saturday Night Fever written and directed (and featuring a short, "Cobra"-looking cameo from) Sylvester Stallone. Why I would rent this movie, which has a 0% rating on Rotten Tomatoes, is none of your concern. Okay, it's for a project involving '80s movies set in NYC. Anyway, a critical score that terrible is always worthy of a must-be-seen-to-be-believed glance.

So, I'm watching the movie, and it's really not that bad. I must note that I don't particularly like the original except for the music, and Staying Alive pays off nearly as well as far as cheesy soundtracks go (Sly did his brother Frank a favor by prominently featuring his music and his acting "talent"). Compared to SNF, the sequel has double the leading ladies (Cynthia Rhodes and Finola Hughes), and both are actually attractive and so-so actresses, unlike the awful Karen Lynn Gorney. And the plot, in which Tony Manero (John Travolta) tries to make it as a dancer on Broadway while disrespecting the woman who loves him by aiming instead for the stuck up star, could definitely be worse.

For at least the first two acts, I wondered how Entertainment Weekly could really name this as the worst sequel of all time, above Jason Takes Manhattan, above Jaws the Revenge, above Batman & Robin (?!?!?). Then it came: the seemingly 8-hour production of Tony's Broadway debut in Satan's Alley, possibly the worst thing I've ever seen in a movie. There's screaming, there's tacky costumes, there's ... actually, I don't think I can adequately describe the horror because I either completely tuned out or have since blanked it out of my mind. All I know is that the movie was ruined, I lost interest in finding out who Tony ends up with or how or why and I barely reconnected with my TV screen to barely appreciate the final end-credit "strut" to the titular (if you don't mind the difference in spelling) Bee Gees tune.

I honestly can't recall another scene or sequence or third act that is so detrimental to the enjoyment of an otherwise watchable (if not good) movie. Can you?